A continuing concern of users of scuba gear relates to the desire to maximize diving time while maintaining an adequate safety margin. The human body includes numerous distinct tissue groups which absorb and retain gases at varying rates in relation to numerous factors including but not limited to atmospheric pressures. Thus, for example, each tissue group will reach a predetermined saturation threshold at varying rates depending on the prevailing atmospheric pressure and dive depth. The factors affecting the rate of absorption as well as the rate in which gases are expelled (off-gassed) from the tissues are collectively known within the scuba diving field as J-factors.
Empirical studies have shown that a diver can safely return to the surface without the need for decompression stops so long as none of the tissue groups are saturated. Correspondingly, once the diver has exceeded the saturation threshold, additional precautions, i.e., decompression stops, will be necessary to ensure sufficient time for the saturated tissue to expel excess gases.
Conventional dive planners and computers simplify the calculation of the time a diver can spend at a given depth without the need to factor in decompression stops (no-stop time). However, these planners and computers present a one-size-fits-all approach which fails to account for variations in environmental conditions as well as the individual physiological condition of the diver. Importantly, these factors impact the rate of gas absorption of the aforementioned tissue groups.
For example, the tissue of a diver who has engaged in multiple dives in a short span of time will reach saturation faster than it would for that diver's first dive. Likewise, the tissue of an older diver or a less physically fit diver will reach saturation faster than a younger or more physically fit diver.
By necessity, the calculations embodied in conventional planners and computers incorporate a significant (fixed) safety factor to ensure the safety of the user despite the fact that they arc unable to compensate for the above-described variations in the rate of gas absorption.
The magnitude of the above-described safety factor unnecessarily curtails the dive time to ensure that none of the tissue groups become saturated, i.e., to avoid the need for decompression stops. The use of an unnecessarily large safety factor wastes the diver's time and resources and restricts diving flexibility.
Consequently, there is a need for a diving computer which enables the user to tailor the no-stop time calculations to reflect existing environmental conditions as well as factors pertaining to the diver's physiological condition, i.e., account for the J-factors.
Another concern for users of scuba equipment relates to the need to display various dive related information in a convenient manner. Due to various safety concerns, divers must periodically refer to the dive computer to monitor their current depth, dive time duration, and remaining no-stop time.
Conventional dive computers are inflexible in that they do not provide the diver with the ability to select the type of information displayed. Notably, conventional dive computers fall into two categories--minimalist displays which display only the bare minimum information which every diver must track, and maximalist displays which display a plethora of dive-related information.
Minimalist displays are ideal for novice divers in that they force the diver to focus on the important information. However, these minimalist displays do not provide sufficient information for intermediate and advanced divers who wish to track additional dive related parameters. Moreover, existing maximalist displays are unsatisfactory even to advanced divers because they present too much information at one time, and do not allow the diver to select the type of information displayed.
Therefore, there is a need for an improved diving computer including a customizable display feature allowing the user to select the type and amount of information shown on a display.
Yet another concern for users of scuba equipment relates to the need to warn the user with respect to various alter conditions such as, for example, too rapid an ascent, the need for decompression stops, and low battery state. Conventional diving computers use light sources, such as LED's mounted in the casing, situated outside the display, for warning purposes. Alternatively, some diving computers utilize audible beeps to alert the diver that something is wrong. None of these methods is ideal.
During an emergency situation, the diver has a very limited ability to comprehend information. Moreover, the diver's response time is hampered if the information is unclear or needs to be found in several locations. Importantly, reduced visibility conditions may make it difficult or impossible for the diver to see a flashing LED light. Also, thick hoods such as used in dry suits impair the divers ability to adequately hear audible beeps clearly enough to ensure that a warning would be always noticed.
Consequently, there is a need for an improved method for alerting the diver to respond to an emergency situation.
The renting or sharing of diving equipment raises the need to clear the information stored in the diving computer. Previous approaches to resetting (clearing) stored data have included the use of mechanical switches that turn off the power to the unit making it "forget" the stored data. These mechanical switches such as HALL transducers or REED switches are prone to physical shock and corrosion.
Consequently, there is a need for an improved method for clearing stored data which does not rely on mechanical switches.
In response to these problems, one object of the present invention is to provide an improved dive computer which enables the user to tailor the no-stop time calculation to account for environmental and physiological parameters (J-factors).
Another object of the present invention is to provide an improved dive computer having user customizable display features allowing the user to display the type and amount of data displayed.
Another object of the present invention is to provide an improved dive computer whose display promptly alerts the user of an alert condition.
Yet another object of the present invention is to provide an improved method for clearing a dive computer of diver-specific parameters without the use of mechanical switches.